package com初.com.unit9_9;

/**
 * @author 李琦 on 2021/7/31.
 * @version java version "16.0.1" 2021-04-20
 */
public class teat {
    public static void main(String[] args) {


        Master master = new Master();
        Cat cat = new Cat();
        Dog dog = new Dog();//向上转型(自动的),以前是Pet pet=new Dog();
        Bird bird=new Bird();

        master.feed(cat);
//      master.feed(bird);
//      master.feed(dog);
    }
}